Are all gains in Interactive Brokers US classified as misc income, even stocks?

I've been living in Japan for 10+ years and have PR (probably relevant for the purposes of discussing taxes).

For a while I thought that as long as the broker I use is in Japan, stock gains can be classified as capital gains and be taxed favorably (譲渡所得 – 20.315%).

However, I use IBKR US and they have not moved my account to IBKR JP, so technically the broker I am using is not in Japan, despite having a Japanese presence. I am thinking as of now, everything I trade are classified as derivatives, which means I am taxed as 雑所得 (misc income).

Do we have any guidance on this?